Fluid motor



Nov. 26, 1940. D, SCHQTT 2,222,689

' FLUID MOTOR Filed Sept. so, 1938 INVENTOR ATTORNEYS 40 bands against the adjacent projecting blade in Patented Nov. 26, 1940 I i UNITED STATES PATENT OFFICE Donald Edward Schott, Bronx, N. Y, assignor to Thomas O. Wilson, Inc., New York, N. Y., a corporation of New York Application September :0, 1938, Serial No. zazssa '1 Claims. (01. 121-87) This invention relates to motors and has parinlet and outlet ports. with this construction, ticular reference to a novel fluid-operated mothe motor is double-acting instead of 'singletor. The new motor is of a simple construction acting, in that each blade is acted on twice by adapted for-manufacture at low cost and is easy compressed air during a single revolution of the to assemble and to take apart for inspection or. rotor, once in each chamber. While double-act- 5 replacement of parts. Also, the motor of my ining motors of this type have definite operating vention is compact so that it may be used in readvantages over single-acting motors; their comstricted spaces, as, for example, in boiler tubes mercial use has been limited, at least partly by where it is used for operating cleaning devices. reason of their-relatively high cost. That is,'in'

For illustrative purposes the invention will be the manufacture of these motors, the cylinder 10 described and illustrated in the form of a motor must be provided with two parallel bores of operable by compressed air, although it will be greater radius than the rotor, one merging into understood that the principles of the invention the other, and theinside walls of the cylinder are applicable as well to other forms of motors, where the bores merge are made tangential to the such assteam driven motors. adjacent curved walls of the bores, as shown in 15 One form of air motorcommonly employed a patent to C. F. Overly, No.- 1,104,070. The forheretofore includes a rotor having longitudinal, mation of these tangential portions requires excircumferentially spaced, radial slots, in each of pensive filing operations which must be perwhich a blade is mounted for radial movement in formed carefully and accurately. Also, the seals the slot. The rotor is mounted in a cylinder or a formed by engagement of the tangential portions 20 liner, the internal radius of which is greater than and the rotor, between the inlet and exhaust the external radius of the rotor, the IOtOI' being ports, are merely straight line cgntacts' and aceccentric with respect to the axis of the cylinder cordingly are subject to]ea,kage so that it contacts the cylinder wall along a line One feature of. t present invention, t

parallel to the cylinder axis and forms with the fore, resides in the provision of novel. 1 yl nd a chamber which is Crescent-Shaped in acting air motor which overcomes these disad cross section. As the rotor turns, the blades vantages of primmotors of'thj typeand which moving into the chamber are thrown outwardly is at once n t simple in construction and in the rotorslots against the chamber wall under easy to m uf tu An air motor made in the action of centrifugal force, and air is adcol-dance with my invention comprises a cylindel; 30 mitted into the side of the chamber from which having three parallel bores therein which merge the blades enter and is exhausted through a port together one of the bores having a radius'equal near the opposite side of the chamber. When to that of the rotor and being located between the air is admitted, it is prevented from expandthe other Accordingly when the rotor is ing directly into the exhaust port by the projectmounted m cylinder h two outer bores 3;) ing blade in the chamber on one side of the inlet form cresbenbshaped chmnbers one on Each port and by the line contact between the rotor of the rotor while the walls oftheintermediate. and the cylinder on the other side of the inlet port. bore which join the curved walls of the outer Thus, the air, after entering the chamber, exbores. closely engage the rotor on opposite sides over substantial sections of its cylindrical surface, thereby forming eilective seals between the two chambers. With this construction, the inthe chamber and forcesit toward the outlet port, thereby turning the rotor. Before the blade reaches the outlet port, the next blade enters the chamber and passes to a position between the tenor of the cyhnder may be formed wlthout the inlet and outlet ports, sothat when the first blade usual flung operations by slmply qnllmg the r passes over the outlet port to exhaust the air bethree bores! thereim- .5150, the P hind it, the second blade prevents the air which closely approximates idea1 cylmder m Winch is admitted behind it from expanding directly ini biades. could move to thelr 9u te t pos to the outlet port. tions immediately after the admission of air be- It has been proposed heretofore to improve the hind themt n e cylinder of the new operation of motors of this type by so forming motor, 98011 d after passing from beneat the cylinder that when the rotor is mounted n Of t e Se Sur ws Of'thB i te me ate therein, it contacts the cylinder wall along two bore and eyo t P t W re lf is tted diametrically opposed lines and separates two behind it, approaches its outermost position more crescent-shaped chambers, each having the usual rapidly, for equal increments of angular motion, 55

than is possible in a cylinder employing tangential surfaces.

Another feature of the invention resides in the provision of a novel air motor in which the compressed air supplements the action of centrifugal force in urging the blades outwardly in the rotor, and which includes means for valving the air acting on the blades, so that the air is effective to force the blades positively against the walls of the expansion chambers immediately upon passage of the blades into the chambers. In the preferred form of the new motor, the compressed air is admitted into the slots in the rotor at one end thereof and beneath the blades, the admission of air into each slot being controlled so that it starts only when the blade in the slot is retracted under one of the sealing surfaces. The admission may continue, however, after the blade has passed into one-of the expansion chambers, at which time the air passes from beneath the blade into the chamber through one or more inlet ports on the expansion side of the blade. The blades and slots are so formed that'when a blade is retracted under one of the sealing surfaces, the inlet ports leading from the bottom of the slot are not fully exposed, whereby a back pressure is built up under the blade which, as soon as the blade enters the chamber, is released and urges the blade forcibly against the chamber walls.

It will be apparent that the air admitted into each slot acts first to build up a back pressure in the slot which forces the blade outwardly as it moves into an expansion chamber, and then acts on the blade in the expansion chamber to drive the rotor. While the blade is passing beneath one of the sealing surfaces of the intermediate bore,

the air under it has ample time to build up a back pressure which, in conjunction with the centrifugal force acting on the blade, is sufficient to throw the blade outwardly with considerable force against the chamber wall as soon as the blade enters the chamber. Accordingly, the blades, as they passthrough the expansion chambers,form better seals between the inlet and exhaust ports than in prior motors of the same These and other features of the invention may be better understood by reference to the following detailed description taken in conjunction with the accompanying drawing, in which Fig. l is a longitudinal section through one form of the new motor;

Figs. 2 and 3 are sections on the lines 22 and 3-3, respectively, in Fig. 1;

Fig. 4 is an end view of Fig. 1;

Fig. 5 is a longitudinal section on the line 5-5 in Figs. 2 and 4, with the rotor removed; Fig. 6 is a longitudinal section through part of the rotor on the line 66 in Fig. 2, showing the shape-of the blades, and

Fig. '7 is a side view partly in section showing parts of a modified form of the new motor.

In the drawing, the numeral l0 designates a metallic casing which is generally cylindrical in form and has a hollow hub portion l I on the front end, the hub being tapered and having diametrithe motor shown in cally opposed flattened portions ll. Ametal cyl inder or liner l2, fitted closely in'the casing through the open, rear end thereof, is formed with three bores, two of which, designated l3, are near opposite sides of the liner, and the third of which, designated i3, is centrally located in the liner, the bores being in parallel relation with the bore l3 arranged between and merging with the outer bores. Mountedin the interior of the liner is a cylindrical rotor H, the main body of ,which has a radius substantialy equal to the opposite sides over an angle of approximately 25" at each side.

At its front end, the rotor is formed with an integral shaft or spindle I6 which is smaller in diameter than the main body of the rotor and extends through a bushing i1 disposed in the hub l 1-. At its outer end, the shaft 16 is threaded, as shown at l6, so that it may be connected to the device to be driven. A wear platel8, through which the shaft i6 extends, is disposed in the front part of the casing and is engaged on one side by the front end of the liner l2 and the corresponding end of the main body of the rotor, and on the opposite side by a shoulder ill in the casing. The liner, wear plate and easing are held against relative rotary movement by one or more pins I9, each of which extends through an openmore pins 23, each of which enters aligned re-- cesses in the liner and bearing member. A 1101- a low retainer nut 24 is threaded in the open end of the casing and clamps the bearing member 22 against the liner, the bearing member and nut being so formed as to provide an annular chamber 25 between them. The chamber 25 may be supplied with compressed air through a com-.

pressed air line (not shown) threaded in an opening 24' in the rear end of the nut.

The main body of the rotor I4 is formed with a plurality of radial slots ll' extending lengthwise of the rotor and spaced equidistantly around the cylindrical surface thereof. In the motor illustrated, the rotor is formed with six radial slots, but it will be understood that any other desired number may be employed. In each of the slots I4 is a blade 21 which fits closely in the slot and is movable radially therein. Preferably, the blades 21 aremade of a light-weight material, such as fiber or Bakelite, although metal blades may be used when desired. As shown particularly in Figs. 1 and 6, the blades are generally rectangular in form and are of a length equal approximately to the length ofthe main body of the rotor, so that the opposite ends of the blades, which are straight, are in substantial engagement with the wear plate l8 and the bearing member 22, respectively. The blades are of a width such that when they are retracted in the slots by engagenient of their outer edges with the wall of the intermediate bore l3 (Fig. 2) there is a slight clearance between the inner edges of the blades and the bottoms of their respective slots.

The! spindle 2| is formed with extensions ll" of the slots M, the extensions terminating a substantial distance inwardly from the end of the spindle. The slot extensions l4" cooperate with a pair of inlet openings 28 and 28' in the bearing member 22, which communicate with the annular chamber 25. The inlet openings 28 and 28 are diametrically opposed and each of them subtends an angle of approximately 90 over the part of the spindle 2| in which the slot extensions are formed. Accordingly, compressed air may be supplied from the chamber 25 through the inlet openings 28 and 28 to those slot extensions I4 which are exposed under the inlet openings, and from the exposed extensions It" to the respective slots II where the air passes beneath the blades.

The rotor I4 is adapted to be moved in a clockwise direction, as seen in Fig. 2, by compressed air admitted to the chambers l5 through a series of inlet ports, 29 communicating with the bottoms of the slots. Each slot is preferably pro vided with a plurality of ports 29 spaced along its length, the ports being located on the lagging side of the blade in the slot. lilach of the ports 29 has a beveled bottom which inclines downwardly toward the corresponding slot i4 and terminates at the bottom of the slot. Thus, when any one of the blades is-retractedby engagem'ent with the wall of the central bore l3, as shown in Fig. 2, the inner edge of the blade partially covers the corresponding inlet ports 29 so that the passage of air from the bottom pf-the slot to the corresponding inlet ports is greatly restricted. I 4

The liner I2 is formed in its cylindrical surface with diametrically opposed grooves which, with the casing l0, provide longitudinal exhaust passages 32 and 32'. The exhaust passages are disposedbetweenthe inlet openings 28 and 28', as shown in Figs. 2 and 3, and communicate with the chambers l5 through a plurality of outlet ports 3| formed in'the liner. The wear plate I8 is provided with a pair of diametrically opposed, milled notches 33 and 33 which coincide with the passages 32 and 32', respectively, in the liner, and the rearfend of the casing is formed with openings 34 and 34 which coincide with the notches 33 and 33", respectively. Accordingly,

air may be exhausted from one of the chambers l5 through the-exhaust ports 3|, passage 32, and openings 33 and 34, and air in her l5 may be exhausted through outlet ports 3i, passage 32' and openings 33' and 842 in .the operation of the motor, compressed air s pplied to the annular chamber 25 passes through the inlet openings 28 and 28' and enters the slot extensions M" as the latter pass under the inlet openings. As shown in Figs. 2 and 3, the inlet opening 28 is so positioned in the liner that it commences to supply air to each slot extension" l4"- as the corresponding blade 21 moves under the upper wall of the central bore I 3 and just before the blade reaches a vertical position.

. l y, the inlet opening 28 is so positioned in the. iner that it begins to supply air to ea h'6f the slotv extensions l4", as the corresponding blade 21 passes over the lower wall of the central bore i3 and just before the blade reaches a vertical position; .The compressed air which is thus admitted into the uppermost and lowermost slot extensions 14" passes into the small spacesbetween the bottoms of the corresponding slots and the blades in the slots. 'Since' the blades are' retracted by engagement with the wall of .bore 13' when compressed air is flrstadmitted to their corresponding slot extensions M", the air cannot pass freelylfrom beneath the blades to the corresponding. inlet ports 29, and accordingly aback pressure is built up under the tor the other champasses over the exhaust blades which urges them outwardly against the wall of bore l3. As the rotor continues to turn, each of the blades engaging the wall of the central bore I3" moves toward one of the crescent-shaped chambers l5 and finally passes into the chamber. At this point, the back pressure beneath the blade, as well as,th'e centrifugal force on the blade, act to move the blade outwardly against the wall of the outer bore I 3 through which the blade is moved, whereby the inlet ends of. the correspond- 1 ing ports 29 are more fully exposed. .At the same time, the outer 'ends of the corresponding inlet ,ports 29 move out from underthe wallof the central bore. l3 and into the chamber l5, so that they are uncovered. Compressed air then passes from the space beneath the blade through the inlet ports 29 to the lagging side of that part of the blade which projects into the chamber IS, the air expanding as it reaches the chamber l5 and urging the blade and rotor in a clockwise direction.

As shown in Fig. 3, the'inlet openings 28 and 28' are of such a width that the admission of air to each of the slot extensions I4" continues until the corresponding blade has traveled approximately 90 from its vertical position. Accordingly, during this movement of the blade, it is subjected at the bottom to the line pressure which urges the blade outwardly against the wall of theliner, and is subjectedon its lagging side to the pressure of the expanding air -ad mitted through the inlet ports 29 to thechamber 15. In addition, the blade is subjected to a centrifugal force incident to rotation of -'the ropressure on the bottom of the blade in forcing it outwardly and holding it firmly against the wall of the liner. any substantial leakage of air between t e blade and the liner wall is prevented.

H, which supplements the actionof the airy When the blade has traveled 90' from its vertie cal position under -one wall'oi' the central bore l3, it reaches the widestpart of the chamber i ii and assumes its outermost position, and

thereafter, rotation of the rotor l4 causes the blade to move inwardly and approach one of the series of exhaust ports ;#3l, 3| As the blade ports, the expanded air behindqihe blade passes through the exhaust ports into one of the exhaust passages 32,- 32 and out through thewear plate 18 and the rear end of the casing. The blade then passes under the opposite wall of the central bore l3 to a position wherethe corresponding slot extension I4" is underan inlet opening ,28, 28', whereupon the cycle is repeated in the other chamber l5.

With this construction, the liner or cylinder I2 drilling the bores l3 and ground after the liner has been hardened, thereby *may be made expeditiously and at low cost by I I3. The bores may be preventing leakage of air between the blades and liner due to distortion of the liner'result'ing from the hardening operation; By employing a liner of the formdescribed, the usual tangential portions connecting the two-outer bores are avoided and the expensive filing operation performed in formingthese tangential perhaps is eliminated.

-Also,-the seals between the two chambers: l5 are prior-motors of this type, in that the seals of the new motor-are vastly superior to those in formed by closely fitting surfaces of the rotor and liner, whereas in prior motors, the seals are generally formedby line contacts. between the rotor and liner Another advantage of theliner of the groove.

7o opposite sides of thecylinder hers, whereby the blades perform a greater amount of work.

It will be apparent that by providing air inlet means at the ends of the rotor slots, the cominto the slots beneath the pressed air may pass blades and supplement the action of centrifugal force in holding the blades against the cylinder wall, whereby chattering of the blades and leakage of air between the blades and cylinder wall are more effectively prevented. Since the admission of air to each of the rotor slots is commenced when the corresponding blade is near its vertical position under a wall of the bore IS, a substantial amount of back pressure may he built up in the slot under the blade while the latter is' moving along the wall of the bore l3 and before it reaches one of the chambers l5. During this movement of the blade, the outlet ends of the corresponding ports 29 are closed by the wall of the bore [3, and the inlet ends of the ports 29 are substantially closed by the bottom of the blade, so that the desired back pressure under the blade may build up quickly. If desired, the spindle l6 maybe formed with an oil groove 36 forming an extension of one of the rotor-slots l4. Thus, when the slot'H' connected to the groove 36 is supplied with air from its extension H", which occurs twice during each revolution of the rotor, once at each of the inlet openings 28, 28',.oil from the rotor or an oil supply (not shown) is blown by the air along the slot and the groove 36 and eventually'seeps out between the bushing I1 and spindle Hi from the end The groove, therefore, provides for a positive distribution'oi' oil between the spindle and its bushing.

Instead of employing the bearing member 22 made of a single piece, the bearing shown in Fig. '7

45 may be employed. As there shown, the bearing is designated by the numeral 22' and is open at its rear end and provided with an integral threaded extension 38. A replaceable bushing 39 is fitted closely in the bearing and may be clamped against the rear end of the main body of the rotor by a cap 4 0 screwed on the threaded portion 38. The bushing 39 is formed with openings 39" adapted to align with inlet openings ll in the bearing, corresponding to the openings 28, 28' in the bearing 22. In order that the openings 39' will be proper-,

ily aligned with the inlet openings I l in the bearing when the .parts are assembled, I prefer to form the bushing 39' with a slot 42 in which an inwardly projecting part of the bearing extends, where- 9 by the bushing and hearing are held against relative rotation. It will be apparent that with the construction shown in-Fig. '7, the bushing 3,! may be readily replaced by simply unscrewing the cap 40, removing the bushing, and inserting a new bushing in the bearing.

I claim:

. 1. A fluid-operated motor comprising a cylin' der having three parallel bores therein merged together, two of the bores being disposed near d the third being substantially centrally local: in the cylinder between the other two, a rotor in the cylinder fl ted closely in the central bore and forming with theouter here's a pi .r of crescent-shaped chambers,

75 the rotor having a plurality of longitudinal, radial slots separated from each other and having bottom walls, a blade movable radially in each slot and operable to engage the walls of the bores as the rotor turns in the cylinder, the width of each blade being less than the depth of its slot, means for admitting fluid under pressure into one end ofeeach slot in the space under the corresponding blade when the blade engages the wall of said central bore, the pressure of the fluid urging the blade outwardly against said last wall, means for cutting off the supply of fluid to each slot when the slot travels a predetermined distance beyond said last wall, ports in the rotor for admitting fluid under pressure from beneath each blade to said chambers onthe lagging side of the blade to drive the rotor, the inlet end of each port being substantially covered by the corresponding blade when the latter engages the wall of said central bore, whereby back pressure of the fluid der, a rotor in the cylinder including a main body, and spindles projecting from opposite ends of the body, the body having a plurality of longitudinal, radial slots and one of the spindles having extensions of said slots, a mounting for said last spindle having an inlet opening for admit-v ting fluid under pressure into said slot extensions as the latter pass under the opening, a blade movable radially in each of said slots and adapted to engage the cylinder wall, means for admitting fluid under pressure from said slots into the cylinder to act on the blades and drivethe rotor, and means for exhausting fluid from the cylinder.

3. A fluid-operated motor comprising a cylinder, a rotor in the cylinder including a main body, and spindles projecting from opposite ends of the body, the body having a plurality of iongitudinal, radial slots and one of the spindles having extensions ofsaid slots, a bearing for said last spindle having an inlet opening for admitting fluid under pressure into said slot extensions as the latter pass under the opening, a blade movable radially in each of said slots and adapted to engage the cylinder wall, means for admitting fluid under pressure from said slots into the cylinder to act on the blades and drive the rotor, and means for exhausting fluid from the cylinder.

4. A fluid-operated motor comprising a cylinder; having three parallel bores therein merged together, two of the bores being disposed near opposite sides of the cylinder and the third being substantially centrally located in the cylinder between the first two, a rotor in the cylinder fitted closely in the central bore and forming with the outer bores a pair of crescent-shaped chambers, the rotor including a main body and spindles projecting from opposite ends of ,the body, the body having a plurality of longitudinal, radial slots and one ofthe spindles having extensions of said slots, a mounting for said last spindle having an inlet opening for admitting fluid under pressure into said slot extensions as the latter pass under the opening, a blade movable radially in each of said slots and adapted to engage the walls of the bores as the rotor turns in the cylinder, means for admitting fluid under pressure from said slots into said chambrs to act on the blades and drive the rotor, and

means for exhausting fluid from said chambers.

. together, two of the bores being disposed near opposite sides of the cylinder and the third being substantially centrally located in the cylinder between the first two, a rotor in the cylinder fitted closely in the central bore and forming with the outer bores a pair of crescent-shaped chambers, the rotor including a main body and spindles projecting from opposite ends of the body, the body having a plurality of longitudinal,

radial slots and one of the spindles having ex- 1 5 opening for admitting fluid under pressure into blade when the blade passes from under said wall each of said slot extensions when the ,corresponding blade is under a wall of said central bore, means for admitting fluid under pressure into one of said chambers from beneath each into the chamber, and means for exhaustin fluid from said chambers,

6. A fluid-operated motor comprising "a cylinder, a. rotor in the cylinder including a main body and spindles projecting from opposite ends of the body, the body having a plurality of longitudinal, radial slots and one of the spindles having an oil groove forming an extension of one of said slots and adapted to receive oil therefrom, supporting means for said spindles, a blade movable radially in each of said slots and adapted to engage the cylinder wall as the rotor turns in the cylinder, means for admitting fluid under pressure into the end of each slot opposite said grooved spindle as the rotor turns, whereby the fluid pressure forces oil through one of said slots and the oil groove leading from it, means for admitting fluid under pressure from said slots into the cylinder to act on the blades and drive the rotor, and means for exhausting fluid from the cylinder.

7. A fluid-operated motor comprising a cylinder, a rotor in the cylinder-including at least one longitudinal slot having a bottom, a blade movable in the slot and .adapted to engage the cylinder wall, meansfor admitting a. fluid under pressure into one end of the slot under the blade, the rotor having a port extending outwardly from the bottom of the sloton the lagging side of the blade for admitting fluid into the cylinder to drive the blade, the slot having a part extending upwardly from-the bottom to form a seat for the blade above the bottom, the seat and blade, forming a valve for cutting oil" the flow of fluid into the port from the space between the blade and the bottom of the slot when the blade is retracted in the slot, and means for exhausting fluid from the cylinder.

DONALD EDWARD scno'rr. 

